Hydrocracking process to produce gasoline and turbine fuels



1966 c. c. WILLIAMS m, ETAL 3,230,154

HYDROCRACKING PROCESS TO PRODUCE GASOLINE AND TURBINE FUELS 2 Sheets-Sheet 1 Filed June 13, 1963 2 .5: 1 2 2 L 5&2;

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MORTIMER D. ABBOTT BY: Nil L06? THEIR ATTORNEY 1965 c. c. WILLIAMS m, ETAL 3,230,154

HYDROCRACKING PROCESS TO PRODUCE GASOLINE AND TURBINE FUELS CURTIS C. WlLLIAMS III MORTMER D. ABBOTT THElR ATTORNEY HYDROCRACKING FEED United States Patent M 3,230,164 HYDROCRACKING PROCESS T0 PRODUCE GASOLINE AND TURBINE FUELS Curtis C. Williams III, Berkeley, and Mortimer 1). Abbott, Orinda, Calif., assignors to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed June 13, 1963, Ser. No. 287,644 4 Claims. (l. 208-89) This invention relates to a hydrocarbon conversion process and more particularly to a hydrocracking process for the conversion of high boiling mineral oil fractions to gasoline and aviation turbine fuel.

Hydrocracking is old and was practiced commercially before and during World War II, principally in Germany for middle oil from the liquid phase hydrogenation of coal and in England for creosote from coal tar and gas oil from petroleum. Catalytic hydrocracking of mineral oil fractions has received renewed attention, particularly in the United States, during the past few years, Technical advances and economic factors are such that hydrocracking is now more generally profitable.

In a hydrocracking process, high boiling mineral oils are converted to low boiling fractions, especially fractions in the gasoline and the middle distillate boiling range. The high boiling mineral oils, for example, straight run gas oils and cracked cycle oils, are highly aromatic in nature and as a result, the products contain a high proportion of ring compounds. This is generally true even when the high boiling mineral oil is subjected to a hydrofining process to remove nitrogen compounds which poison acidic hydrocracking catalysts, prior to the hydrocracking conversion. Little hydrogenation of arcmatics results, for example, from the use of a hydrofining catalyst which is selective for nitrogen removal or from the use of relatively low severity operations which are sufiicient to provide a relatively low residual nitrogen content but at which severity little hydrogenation of aromatics occurs. A hydrocracking process itself, also effects the nature of the products; for example, a high aromatic content may be obtained as a result of high temperature non-ionic cracking or from operation with little or no recycle of high boiling fractions. The type of hydrocracking catalyst used also aifects the nature of the products.

With respect to product gasoline fractions, a high aromatic content is desired since aromatic hydrocarbons have a high octane rating. The gasoline fractions, particularly the naphtha fractions, are amenable to improvement in octane rating by means of a catalytic reforming process to dehydrogenate naphthenes to aromatics. With respect to the aviation turbine fuel fraction, however, aromatics are undesirable since they contribute to poor luminometer number rating and smoke point of the fuel. Smoke point and luminometer number of the aviation turbine fuel fraction can be improved somewhat by recycling to extinction that portion of the reactor effluent boiling above the aviation turbine fuel boiling range. With such recycle operation, however, gasoline fractions obtained are relatively high in parafiins and low in aromatics, therefore they not only have a relatively low octane rating but are less amenable to octane improvement by catalytic reforming. Thus, in hydrocracking, aviation turbine fuel fractions having an aromatic content of up to 30% and even higher and smoke points of about 14 or lower are obtained. Such values are entirely unsuitable in view of present limits of a maximum aromatic content of 20% v and a minimum smoke point of 21.

In accordance with the present invention, high quality aviation turbine fuel is prepared by hydrocracking high boiling hydrocarbon fractions at suitable operating conditions of temperature, pressure and the like to effect a 3,230,164 Patented Jan. 18, 1966 substantial conversion of the hydrocarbon fraction to lower boiling fractions in the gasoline and aviation turbine fuel boiling range, separating from the effluent a fraction comprising components in the gasoline boiling range and a fraction comprising components in the aviation turbine fuel boiling range, subjecting the fraction containing the aviation turbine fuel components to a hydrogenation process employing an active hydrogenation catalyst to reduce the aromatic content of the fraction, and recovering a high quality aviation turbine fuel fraction from the hydrogenated fraction.

High boiling hydrocarbon fractions used as feed to the present process include straight-run gas oils and cracked cycle stocks boiling between about 400 and 1050 F. and include such fractions as middle distillate fractions boiling in the range from about 400600 F., heavy gas oil fractions or cycle stocks boiling in the range from about 500 to about 950 F. and residual type stocks, preferably after removal of asphaltcncs, such as deasphalted oils recovered from the solvent extraction, e.g., propane solvent, of residual fractions such as pitch. The preferred feeds to the process of the invention are the heavy gas oils and cycle stocks boiling in the range from about 500 to about 950 F.

Any suitable hydrocracking catalyst can be employed. Such hydrocracking catalysts are well known in the art and in general comprise a hydrogenating-dchydrogenating component on an active acid-acting support having the ability to crack hydrocarbon oils. Such supports include acid-acting refractory oxides and in particular the acidacting refractory oxides comprising a major amount of silica, such as silica-alumina, silica-zirconia-titania, silicaalumina-magnesia, silica-zirconia and the like, acid activated montrnorillonite clays and including certain alumino silicates referred to generally as molecular sieves. The carriers can generally be further activated by the incorporation of small amount of halogen such as fluorine or chlorine, The hydrogenating-dehydrogenating component usually comprises from about 130% by weight of the catalyst and includes for example metals, such as the transitional metals, or their oxides or sulfides, in Groups 13, VB, VIB, VIIB and VIII or mixtures thereof. Particularly desirable hydrogenating-dehydrogenating components are the metals, or their oxides or sulfides, chromium, molybdenum, tungsten, iron, cobalt, nickel or the metals palladium, platinum, silver and copper.

Hydrocracking catalysts can be prepared in any suitable manner such as incorporation of the hydrogenatingdehydrogenating component within the support such as by co-gelation into a hydrogel of the refractory oxide, ion exchange or impregnation into a hydrogel of the refractory oxide, or ion exchange or impregnation of the component into a xerogel of the refractory oxide.

A particularly suitable hydrocracking catalyst is silicaalumina cracking catalyst in association with a form of nickel as the hydrogenating-dehydrogenating component such as, for example, nickel sulfide disposed on a silicaalumina cracking catalyst or nickel-fiuoro-alumino-silicate wherein the nickel and fluoride have been incorporated by co-gelation or ion exchange into a silica-alumina hydrogel. Silica-alumina cracking catalysts are Well known in the art and usually comprise from about 60-90% w. silica and 40-10% W. alumina.

The hydrocracking conversion is effected at a temperature in the range from 500 to about 850 F., a pressure in the range of 750 to 2500, a volumetric liquid hourly space velocity (LHSV) of from 0.5 to 5 and in the presence from about 5,000 to 20,000 standard cubic feet of hydrogen per barrel of oil. The hydrocracking conversion is accompanied by a relatively large consumption of hydrogen, usually from 500 to about 2,000 standard cubic feet per barrel of fresh oil feed.

As mentioned hereinbefore, the acid-acting hydrocracking catalysts are generally susceptible to poisons such as nitrogen compounds in the hydrocracking feed. Therefore, it is generally desirable to subject the hydrocracking feed to a suitable hydrofining process to remove the nitrogen compounds to a substantial degree. The extent to which the nitrogen compounds must be removed depends to a certain extent upon the particular catalyst employed. For example, with nickel sulfide on silicaalumina, it is generally desired to reduce the total nitrogen content of the feed to less than 10 p.p.m./w., preferably less than 5 p.p.m./w. With other catalysts such as the nickel-fluoro-alumino-silicate, total nitrogen content of the feed of up to about 75 p.p.m./w. and even higher can be tolerated. In addition to the removal of nitrogen compounds, a substantial portion of organic sulfur and oxygen compounds are decomposed in the hydrofining operation, although the residual sulfur content is generally appreciable for most high boiling oils at usual hydrofining conditions.

Any suitable hydrofining catalyst can be employed in the hydrofining step. Such catalysts are well known in the art and may comprise one or more of the transitional metals, or their oxides or sulfides, and especially one or more of the metals of Group VIB and Group VIII, and their oxides and sulfides, such as for example, molybdenum, tungsten, cobalt, or nickel. It is generally preferred to use an iron group metal together with a group VIB metal, such as tungsten with nickel, or molybdenum with cobalt or nickel. The catalyst is generally supported on an adsorbent carrier in proportions ranging from about 2 to 25% by weight. Suitable carries include in general the refractory inorganic oxides such as alumina, silica, zirconia, titania, and clays such as bauxite, bentonite and the like. For catalysts having high selectivity for nitrogen removal, the support may be acidic such as, for example, silica-alumina or alumina-boria and the like.

Hydrofining is generally conducted at a temperature in the range from about 550 to 850 F., a pressure of about 500 to 3000 p.s.i., a hourly liquid space velocity 'of from about 0.1 to 5, and a hydrogen rate of about 1000 to 10,000 standard cubic feet per barrel.

Efiluent from the hydrocracking conversion zone is separated into a gasoline fraction and an aviation turbine fuel fraction and the aviation turbine fuel fraction is hydrogenated with an active hydrogenation catalyst to hydrogenate aromatics to naphthenes. Hydrogenation catalysts comprise one or more metals or the oxides or sulfides, from Group VIB and Group VIII and are frequently supported on a substantially inert porous support, -such as silica, alumina, bauxite, kieselguhr, silica stabilized alumina and the like. Particularly suitable catalysts are the highly active hydrogenation catalysts, such as the Group VIII metals, especially nickel or platinum, supported on a porous support, e.g., silica or alumina. Such catalysts are commercially available, such as, for example, from The Harshaw Chemical Company, 0'101-T (nickel on silica) and from the Universal Oil Products Co., R8 (platinum on halogenated alumina). The highly active metal-containing hydrogenation catalysts are sensitive to sulfur compounds, therefore, it is generally advisable that the sulfur content of the aviation turbine fuel fraction be less than 10 p.p.m./w. and preferably to less than 2 p.p.m./w. Sulfur in the aviation turbine fuel fraction is generally in the form of dissolved hydrogen sulfide and is rather easily removed as will be seen hereinafter.

Hydrogenation of aromatics in the aviation turbine fuel boiling range can be effected at a temperature of about 250 to 600 F., a pressure of about 100 to 2500 p.s.i., a liquid hourly space velocity of from about 1 to and a hydrogen to oil rate of about 1000 to 10,000 standard cubic feet per barrel of oil.

The invention will be more fully understood from 4 a detailed description of the drawing in which FIGURE 1 is a schematic flow diagram illustrating a specific embodiment of the invention and FIGURE 2 is a schematic flow diagram illustrating an alternative specific embodiment of the invention.

With reference to FIGURE 1, the hydrocarbon oil charge such as a heavy catalytic cracked gas oil is introduced through line 1 and is passed together with hydrogen from line 2 through heater 3. The oil and hydrogen, at hydrofining temperature, is passed via line 4 into hydrofining zone 5 wherein organic sulfur compounds and organic nitrogen compounds are converted into H S and ammonia, respectively, by means of a hydrofining catalyst such as described hereinabove. The preferred hydrofining catalyst consists of molybdenum oxide together with cobalt oxide and/or nickel oxide supported on silica-alumina. The silica-alumina based hydrofining catalysts are generally more selective for removing nitrogen compounds from such cracked cycle oils than the alumina based catalysts. Typical hydrofining conditions are a temperature of about 650 to 750 F., a pressure of about 600 to 2200 p.s.i., and a space velocity of about 0.5 to 3. In general the residual nitrogen content in the product becomes lower as the temperature and pressure are increased and as the space velocity is decreased.

Efiiuent withdrawn from the hydrofining zone is passed, after suitable cooling, via line 6 to phase separator 7. A hydrogen gas phase is withdrawn from separator 7 via line 8 and is recycled to the hydrofining zone. It is generally desired to subject this recycle hydrogen to a purification treatment to remove light hydrocarbon gases and more particularly to remove ammonia and hydrogen sulfide. Suitable means for purifying the recycle hydrogen are well known in the art. Hydrogen consumption in the hydrofining reaction will generally be in the range from about to 1500 standard cubic feet per barrel of feed. Consequently, makeup hydrogen from any suitable source can be provided, such as from line 32.

The liquid phase from the separator can, if desired, go directly to the hydrocracking stage; however, it is preferred to pass the liquid via line 9 to fractionation zone 10 wherein dissolved ammonia and hydrogen sulfide, as well as up to about 510% by volume of gasoline and lighter hydrocarbons formed in the hydrofining step are removed overhead. The gasoline can be catalytically reformed if desired. Hydrocracking feed is removed from the fractionation zone 10 and is passed via line 11 through heater 12 and line 13 to hydrocracking zone 14. Hydrogen is introduced via line 15. The catalyst employed in the hydrocracking zone is preferably of the nickel type, for example, nickel sulfide on silica-alumina, or more especially a nickel-fluoro-alumino-silicate catalyst, wherein the nickel is incorporated in a silica-alumina hydrogel. The hydrocracking reaction is an exothermic reaction and it is generally necessary to provide some means for cooling reaction zone, such as by providing multiple beds of catalysts with injection of relatively cool hydrogen between the beds.

The nature of the hydrocracking reaction is not fully known, but the reaction depends to a large extent upon the catalyst employed, the nature of the feed and, of course, the particular operating conditions. In general, it is considered that cyclic compounds react to give lower boiling cyclic compounds as well as a very high proportion of isoparafiins, particularly C -C isoparaflins. This reaction seems to be primarily one of effecting scission of naphthenic rings attached to aromatic rings or aliphatic side chains attached to aromatic rings. This would seem to explain an increasing amount of paraffins in the gasoline boiling range generally encountered as recycle is increased.

Elfiuent from the hydrocracking zone is cooled and is passed via line 16 to phase separator 17. A gas phase is removed from the separator via line 18 and a normally liquid phase is removed via line 19. The gas phase is recycled to the hydrocracking zone with makeup gas being supplied as necessary through lines 31 or 42. The recycle gas can, if desired, be subjected to a hydrogen purification treatment to remove, for example, ammonia and hydrogen sulfide. This purification is particularly desired where there is an appreciable residual nitrogen and sulfur content in the hydrocracking feed. The normally liquid phase withdrawn from separator 17 is passed via line 19 to fractionation zone 20 to effect separation into desired hydrocarbon fractions such as, for example, a C and lighter fraction withdrawn via line 21, a heavy naphtha fraction, e.g., about 180-200 F. to about 350-390 F., removed via line 22, an aviation turbine fuel fraction boiling in the range from about 375 to 525 F. removed via line 23, and a recycle fraction which comprises hydrocarbons boiling above about 525 P. which is removed via line 24 and recycled to the hydrocracking zone. If desired, furnace oil or other fractions can be recovered from this recycle before returning it to the hydrocracking zone.

The heavy naphtha fraction can be routed to gasoline blending facilities via line 25 or, if desired, all or a part of the heavy naphtha can be passed by means of line 26 to catalytic reforming zone 27. Other suitable reforming feed fractions, such as straight-run naphtha, can be added if desired, from line 28. Reforming processes are well known in the art and in general employ a conventional reforming catalyst such as platinum or palladium on halogenated alumina. Older reforming catalysts such a the oxides and sulfides of Co, Ni, Cr, Mo and W can be used if desired. In general, the reforming conditions include a temperature in the range from about 825-950 F., a space velocity between about 1-5, a pressure between about 50-800 p.s.i.g., and a hydrogen rate between about 2500 to 10,000 standard cubic feet per barrel. In the reforming process, naphthenes are dehydrogenated to aromatics resulting in a net production of hydrogen which is removed via line 29 and used as makeup in hydroprocessing as shown by lines 30, 31 and 32. Reformate is recovered from the reforming zone via line 33.

The aviation turbine fuel fraction withdrawn from fractionation zone 20 via line 23 is subjected to purification treatment to remove impurities such as dissolved ammonia and hydrogen sulfide. This is suitably and conveniently efiected in a steam stripper 34. All or a part of the aviation turbine fuel fraction having a sulfur content of less than about p.p.rn./w. and preferably less than about 2 p.p.m./w. is passed via line 35 to hydrogenation zone 36 together with hydrogen from line 30 and/or 41.

In the hydrogenation zone, a hydrogenation catalyst having the ability to 'hydrogenate aromatics to naphthenes is employed. Particularly effective and highly active hydrogenation catalysts comprise a metal of Group VIII such as nickel or platinum on a porous support as described hereinbefore. With such highly active catalysts, the hydrogenation conditions employed include a temperature of about 300 to about 450 F., a pressure of about 200 to 2000 p.s.i., a LHSV of about 3 to 10 and a hydrogen rate of about 1500 to 4000 standard cubic feet per barrel of oil.

Effluent from the hydrogenation zone is cooled and is passed via line 37 to phase separator 38. An aviation turbine fuel fraction substantially reduced in aromatic content is withdrawn from phase separator 38 via line 39 for use after a suitable fractionation to adjust the boiling range if desired as a blending component for finished aviation turbine fuel.

Hydrogen gas removed from phase separator 38 via line 40 can be recycled at least in part, if desired to the hydrotreating zone or used as makup in the hydrocracking (or hydrofining) operation, as shown by lines 41 and 42, respectively. Since the highly active metallic hydrogenation catalysts are sensitive to sulfur, care should be taken to see that the hydrogen employed in the hydrogenation zone is substantially free from sulfur. It is advantageous at times not to employ recycle hydrogen in the hydrogenatio zone but to use hydrogen on a once through basis. This is conveniently carried out by using at least a substantial portion of the makeup hydrogen requirements for the hydrocracking operation as feed to the hydrogenation step via line 30 with residual hydrogen from the hydrogenation step being passed to the hydrocracking operation via line 42. Hydrogen make-up can be obtained from any suitable source such as a naphtha reformer, steammethane reformer, oil gasification process, and the like. In the present process, the combination of hydrofining, hydrocracking and hydrogenation offers a high degree of flexibility in hydroprocessing high boiling mineral oils to high quality products. The refiner is able to select catalyst and operating conditions for each step to provide the selective conversion required to produce gasoline fractions containing a high proportion of aromatics and other cyclic hydrocarbons and jet fuel fraction low in aromatic content. Moreover, better utilization of hydrogen is permitted. This is an important factor since large amounts of hydrogen are consumed in a hydrocracking process and high-cost hydrogen from expensive manufacturing facilities, such as a steam-methane reforming process are generally required. Thus, in conventional two-stage hydrocracking processes, deep hydrogenation of the oil in the hydro'fining and hydrocracking steps produces a low aromatic aviation turbine fuel fraction but consumes large amounts of hydrogen and results in a gasoline relatively high in paraflin content. In the present process, hydrogen requirements are less and both low aromatic aviation turbine fuel and gasoline rich in aromatic and cyclic compounds are produced.

In an alternative method, described with reference to FIGURE 2, hydrocracking feed in line is heated in heater 101 and is passed via line 102 to hydrocracking zone 103 together with hydrogen from line 115. Effluent from the hydrocracking zone is cooled partially and is passed to phase separator 105 to recover a gaseous phase and a liquid phase. Phase separator 105 is substantially at reactor pressure with the usual allowance for pressure drop in lines and heat exchange equipment. At the conditions in the phase separator, hydrocarbons in the reforming feed boiling range are removed primarily in the gaseous fraction via line 106 while hydrocarbons in the aviation turbine fuel boiling range are removed primarily in the liquid phase through line 107.

The actual separation obtained depends to a large extent upon the actual temperature employed, the pressure and the recycle hydrogen rate to the hydrocracking conversion zone. At conventional hydrogen recycle rates and preferred pressure of about 1500 to 2000 p.s.i., e.g., 1800 -p.s.i.a, about 60-90% mole of the catalytic reformer feed fraction (190/375 F.) and from about 5-50% mole of the aviation turbine fuel fraction (375 525 F.) is removed in the gaseous phase with the phase separator at a temperature in the range from about 350 to 450 F. As the temperature of the phase separator is increased, the amount of aviation turbine fuel components withdrawn in the gaseous phase is increased. Thi is not critical in the process of the invention since the aviation turbine fuel components removed in the gaseous phase are primarily those light components which boil at the lower end of the aviation turbine fuel boiling range. The aromatic content of these light components is relatively low as aromatic hydrocarbons are primarily concentrated in the upper end of the aviation turbine fuel boiling range.

The liquid phase Withdrawn from phase separator 105 via line 107 is hydrogenated as described herebefore after suitable treatment in purification zone 108 to remove dissolved H 8, such as a caustic and water wash steam stripping, or the like. Effluent from hydrogenation zone 109 is cooled and is passed by means of line 110 to phase separator 111 wherein hydrogen is removed in the gas phase through line 112 and a liquid hydrocarbon phase is withdrawn via line 113.

The gaseous phase withdrawn from separator 105 is cooled and is passed to phase separator 114 through line .106. A hydrogen-rich gas Withdrawn from separator 114 by means of line 115 is combined with the hydrogen gas phase in line 112 and passed to the hydrocracking zone via line 116. With the particular arrangement shown in FIGURE 2, hydrogen supplied to hydrogenation zone 109 is sufi'icient in amount to meet hydrogen consumption and losses for both the hydrogenation and hydrocracking operations. Liquid withdrawn from phase separator 114 via line 117 is combined with the hydrogenated liquid in line 113 and is passed to a fractionation zone for separation into desired light and heavy gasoline and aviation turbine fuel fractions. The heavy gasoline fraction, which contains components hydrogenated with the aviation fuel fraction in the hydrogenation reactor, is passed to a catalytic reforming zone to dehydrogenate naphthenes as described hereinbefore with respect to FIGURE 1.

The invention will be described in more detail as applied to the hydrocracking of a heavy catalytic cracked cycle oil having typical properties as follows:

ASTM distillation, F.:

IBP 532 10% 612 50% 670 75% 700 Total sulfur, percent wt. 1.35 Total nitrogen, p.p.m./w. 516 Aromatics (ultra violet analysis) mm./ 100 g.:

Mono 41.2

Tri 85.4

Tetra 12.6

This heavy catalytic cracked cycle oil is hydrofined at a reactor inlet temperature of 682 F., a pressure of 1500 p.s.i., a liquid hourly space Velocity of 2.1 and a hydrogen to oil rate of 25003000 s.f.c./b. and with a catalyst comprising cobalt-molybdenum on silica-alumina cracking catalyst. Hydrogen consumption in the hydrofining operation is about 700 standard cubic feet per barrel of oil. Conversion to hydrocarbons boiling below 420 F. is less than by volume.

The hydrocarcking feed obtained from the hydrofining operation has the following analysis:

Total nitrogen, p.p.m./w. 24 Total sulfur, p.p.m./W. 1590 Aromatics (ultra violet analysis) mm./ 100 g.:

Mono 99.1

Tri 19.9

Tetra 5.5

The hydrofined cycle stock was hydrocracked at a tem perature of 670 F. (355 0), pressure of 1500 p.s.i.g., a liquid hourly space velocity (basis fresh feed+recycle feed) of 0.67 and a combined feed ratio (the sum of fresh feed plus recycle feed divided by fresh feed) of 1.5. The hydrogen rate was approximtaely 15 moles of hydrogen in the reactor outlet per mole of feed, and the hydrogen consumption was 1260 standard cubic feet per barrel of feed.

The hydrocracking catalyst was a nickel-fluoro-alumino-silicate catalyst which had been used previously and regenerated. The catalyst was prepared by co-gelling sodium fluoride with silica-alumina (29% alumina) e.g., from sodium silicate and sodium aluminate to obtain a fiuorided silica-alumina hydrogel which was washed to remove sodium and sulfate ions. The washed gel was contacted with an aqueous solution of nickel nitrate to ion exchange nickel into the hydrogel and then washed, dried, and calcined. The finished catalyst contained approximately 4.1% nickel, and 2.5% F. on a weight basis.

Liquid product from the hydrocracking operation was separated into a C and a lighter fraction, a C plus gasoline fraction, an aviation turbine fuel fraction and a recycle fraction comprising hydrocarbons boiling above the aviation turbine fuel boiling range. The gasoline fraction had an ASTM boiling range of 210/334 F., a Research Method Octane rating with three cc. of tetraethyl lead of 88.0 and comprised 44% paraffins, 39% naphthenes and 17% aromatics. The gasoline fraction is a suitable reformer feed. The aviation turbine fuel fraction had an ASTM boiling range of 332 F./520 R, an aromatics content of 27% v., a total nitrogen content of 0.13 p.p.m./w. and a total sulfur content of 4.0 p.p.m./w. Luminometer number of the aviation turbine fuel fraction was 13.6 and smoke point was 17.3 mm.

The aviation turbine fuel fraction was hydrogenated with a nickel on silica hydrogenation catalyst (Harshaw Chemical Company, 0101 T-Ni). Excellent aromatic hydrogenation was obtained at relatively low temperatures and pressures over a wide range of space velocities. For example, at approximately 425 p.s.i.g., 450 F. and space velocities from 1 through 8. The product contained no aromatics as determined by FIA analysis. Hydrogen rate employed ranged from about 2000-3000 standard cubic feet per barrel of oil. Hydrogen consumption at a LHSV of 8 was 650 standard cubic feet per barrel oil charged and the luminometer number of the product was 61.5, smoke point 35.5 mm., and free point -69. Appreciable aromatic hydrogenation was obtained even at relatively low temperatures and high space velocities. For example, at a space velocity of 8.4, a pressure of 200 p.s.i.g., and a temperature of 403 F., aromatic content of the aviation turbine fuel fraction as determined by FIA analysis was only 14% by volume which is well below the maximum permissible aromatic content of 20% by volume.

We claim as our invention:

1. A process for converting a high boiling mineral oil into gasoline and aviation turbine fuel which comprises contacting said mineral oil and hydrogen with a hydrofining catalyst at hydrofining conditions to remove organic nitrogen compounds from the oil, contacting the hydrofined oil and hydrogen in a hydrocracking zone with a hydrocracking catalyst comprising a hydrogenating-dehydrogenating component in association with an active acid-acting cracking catalyst at hydrocracking conditions, partially cooling effluent from the hydrocracking zone, separating the partially cooled eflluent into a gaseous phase containing hydrocarbons in the gasoline boiling range and a liquid phase containing hydrocarbons in the aviation turbine fuel boiling range, contacting the liquid phase and hydrogen with an active hydrogenation catalyst on a substantially inert porous support at conditions including a temperature in the range from about 250 to 600 F. to hydrogenate aromatic hydrocarbons to naphthenes, cooling the gaseous phase and recovering a nor mally liquid hydrocarbon oil, recovering from the normally liquid hydrocarbon oil and the hydrogenated liquid a heavy gasoline fraction and an aviation turbine fuel fraction having an aromatic content less than 20% by volume, and catalytically reforming the heavy gasoline fraction.

2. A process for converting a high boiling mineral oil into gasoline and aviation turbine fuel which comprises contacting said mineral oil and hydrogen with a hydrofining catalyst at hydrofining conditions to remove or ganic nitrogen compounds from the oil, contacting the hydrofined oil and hydrogen in a hydrocracking zone with a hydrocracking catalyst comprising a hydrogenating-dehydrogenating component in association with an active acid-acting cracking catalyst at a temperature in the range from about 500 to 850 F., a pressure in the range from about 1500 to 2000 p.s.i., cooling effluent from the hydrocracking zone to a temperature in the range from about 350 to 450 F., separating the cooled efiluent at substantially hydrocracking zone pressure into a gaseous phase containing hydrocarbons in the gasoline boiling range and a liquid phase containing hydrocarbons in the aviation turbine fuel boiling range, contacting the liquid phase and hydrogen with an active hydrogenation catalyst on a substantially inert porous support at conditions including a temperature in the range from about 250 to 600 F. to hydrogenate aromatic hydrocarbons to naphthenes, cooling the gaseous phase and recovering a normally liquid hydrocarbon oil, recovering from the normally liquid hydrocarbon oil and the hydrogenated liquid a heavy gasoline fraction and an aviation turbine fuel fraction having an aromatic content less than 20% by volume, and catalytically reforming the heavy gasoline fraction.

3. The process according to claim 2 wherein the liquid phase is treated to a sulfur content less than about 10 p.p.m./w. prior to hydrogenation and the hydrogenation is etfected at a temperature in the range from about 300 to 450 F. and a liquid hourly space velocity in the range from about 1 to 15 with a hydrogenation catalyst comprising a Group VIII metal.

References Cited by the Examiner UNITED STATES PATENTS 3,077,733 2/1963 AXe et al. 208-96 3,092,467 6/ 1963 Kozlowski 280-411 3,132,090 5/1964 Helfrey et al 208110 3,172,833 3/1965 Kozlowski et al. 208--58 DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, PAUL M. COUGH- LAN, Examiners.

A. RIMENS, Assistant Examiner. 

1. A PROCESS FOR CONVERTING A HIGH BOILING MINERAL OIL INTO GASOLINE AND AVIATION TURBINE FUEL WHICH COMPRISES CONTACTING SAID MINERAL OIL AND HYDROGEN WITH A HYDROFINING CATALYST AT HYDROFINING CONDITIONS TO REMOVE ORGANIC NITROGEN COMPOUNDS FROM THE OIL, CONTACTING THE HYDROFINED OIL AND HYDROGEN IN A HYDROCRACKING ZONE WITH A HYDROCRACKING CATALYST COMPRISING A HYDROGENATING-DEHYDROGENATING COMPONENT IN ASSOCIATION WITH AN ACTIVE ACID-ACTING CRACKING CATALYST AT HYDROCRACKING CONDITIONS, PARTIALLY COOLING EFFUENT FROM THE HYDROCRACKING ZONE, SEPARATING THE PARTIALLY COOLED EFFLUENT INTO A GASEOUS PHASE CONTAINING HYDROCARBONS IN THE GASOLINE BOILING RANGE AND A LIQUID PHASE CONTAINING HYDROCARBONS IN THE AVIATION TURBINE FUEL BOILING RANGE, CONTACTING THE LIQUID PHASE AND HYDROGEN WITH AN ACTIVE HYDROGENATION CATALYST ON A SUBSTANTIALLY INERT POROUS SUPPORT AT CONDITIONS INCLUDING A TEMPERATURE IN THE RANGE FROM ABOUT 250* TO 600*F. TO HYDROGENATE AROMATIC HYDROCARBONS TO NAPHTHENES, COOLING THE GASEOUS PHASE AND RECOVERING A NORMALLY LIQUID HYDROCARBON OIL, RECOVERING A NORMALLY LIQUID HYDROCARBON OIL AND THE HYDROGENATED LIQUID A HEAVY GASOLINE FRACTION AND AN AVIATION TURBINE FUEL FRACTION HAVING AN AROMATIC CONTENT LESS THAN 20% BY VOLUME, AND CATALYTICALLY REFORMING THE HEAVY GASOLINE FRACTION. 